[Pw_forum] Quick question on Hartwigsen-Goedeker-Hutter pseudopotential

willy kohn willykohn at gmail.com
Sun Oct 5 03:24:43 CEST 2008


Hi, Stefano:
Many thanks for the literature you brought up. That's what I'm looking for.

Best,

Wei


On Fri, Oct 3, 2008 at 3:00 AM, Stefano de Gironcoli <degironc at sissa.it>wrote:

>
> I don't know the details of the generation of  this particular PP but in
> the old good times there has been a very detailed comparison of LDA band
> structure calculation of Ge and GaAs between the PP method and LMTO [GB
> Bachelet and NE Christensen, Phys.Rev.B 31, 879 (1985) ].
> The main result is that in order to get the correct (bad) gap in Ge and
> GaAs  1) scalar relativistic, 2) spin-orbit coupling, 3) 3d-state
> relaxation
> are important... not to mention convergence w.r.t. to cutoff ...
>
> Hope  this helps,
>
>  Stefano de Gironcoli - SISSA and DEMOCRITOS
>
> willy kohn wrote:
> > Hi, Axel:
> >
> > Well, I didn't blame the PP, and I didn't mean to. My question is
> > quite simple. I was told that with a LDA PP, Ge has a vanishing or
> > negative band gap at Gamma point. But with this PP, it has a gap of
> > 0.50 eV (using experimental lattice) or 0.80 eV (after relaxation).
> > I'm not sure what I knew is correct, and that is the reason I wanted
> > another PP to verify.
> >
> > Best,
> >
> > Wei
> >
> > On Thu, Oct 2, 2008 at 2:12 PM, Axel Kohlmeyer
> > <akohlmey at cmm.chem.upenn.edu <mailto:akohlmey at cmm.chem.upenn.edu>>
> wrote:
> >
> >     On Thu, 2 Oct 2008, willy kohn wrote:
> >
> >     WK> Hi, Axel:
> >     WK>
> >     WK> Thanks a lot for your quick answer. I need to do some
> >     calculations on some
> >     WK> compound semiconductors of Ge. But the PP (Ge.pz-bhs.UPF)
> >     provided in the
> >     WK> PWSCF website yeided some results that I don't understand. So
> >     I would like
> >
> >     perhaps it would be useful to explain in more detail what
> >     is confusing you and what calculation you did with what input.
> >     perhaps some people here can comment on it. it is always easy
> >     to blame the pseudopotential (sometimes rightfully so), but
> >     more often than not, the real cause is in not doing a calculation
> >     correctly, or not using a pseudopotential correct.
> >
> >     WK> to use some other PP's to check if I did the calculation
> >     correctly. Any
> >     WK> suggestions?
> >
> >     i have a set of Ge pseudopotentials generated from parameters
> >     for a norm-conserving troullier-martins potential that is in
> >     the extended CPMD psp library. they have seen only very minimal
> >     transferability testing (using an atomic code in bessel basis),
> >     but so far seem to be ok, except for the OLYP one which has a
> >     ghost in the s-channel.
> >
> >     i can send them to you in a private mail, if you are interested.
> >     no guarantees etc...
> >
> >     cheers,
> >       axel.
> >
> >     WK>
> >     WK> Best,
> >     WK>
> >     WK> Wei
> >     WK>
> >     WK> On Thu, Oct 2, 2008 at 11:54 AM, Axel Kohlmeyer
> >     <akohlmey at cmm.chem.upenn.edu <mailto:akohlmey at cmm.chem.upenn.edu>
> >     WK> > wrote:
> >     WK>
> >     WK> > On Thu, 2 Oct 2008, willy kohn wrote:
> >     WK> >
> >     WK> > WK> Dear PWSCF users:
> >     WK> > WK>
> >     WK> > WK> I have a quick question about using
> >     WK> > WK> Hartwigsen-Goedeker-Hutter<
> >     WK> >
> >
> http://cvs.berlios.de/cgi-bin/viewcvs.cgi/cp2k/potentials/Goedecker/abinit/pade
> >     WK> > >pseudopotential
> >     WK> > WK> with PWSCF. Is there any converter to transfer the HGH pp
> >     WK> > WK> format to UPF used in PWSCF?
> >     WK> >
> >     WK> > none that i am aware of.
> >     WK> >
> >     WK> > the GTH pseudopotentials are analytical in real and reciprocal
> >     WK> > space and to incorporate them properly, one would have to do a
> >     WK> > lot of programming. in the CPMD code (from http://www.cpmd.org
> )
> >     WK> > they are treated as a special case, similar to ultra-soft psps.
> >     WK> >
> >     WK> > is there any particularly reason you'd need any of those?
> >     WK> >
> >     WK> > cheers,
> >     WK> >   axel.
> >     WK> >
> >     WK> >
> >     WK> > WK>
> >     WK> > WK> Best,
> >     WK> > WK>
> >     WK> > WK> Wei
> >     WK> > WK>
> >     WK> > WK> Georgia Tech
> >     WK> > WK>
> >     WK> >
> >     WK> > --
> >     WK> >
> >
> =======================================================================
> >     WK> > Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu
> >     <mailto:akohlmey at cmm.chem.upenn.edu>   http://www.cmm.upenn.edu
> >     WK> >   Center for Molecular Modeling   --   University of
> >     Pennsylvania
> >     WK> > Department of Chemistry, 231 S.34th Street, Philadelphia, PA
> >     19104-6323
> >     WK> > tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel:
> >     1-215-898-5425
> >     WK> >
> >
> =======================================================================
> >     WK> > If you make something idiot-proof, the universe creates a
> >     better idiot.
> >     WK> >
> >     WK>
> >
> >     --
> >
> =======================================================================
> >     Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu
> >     <mailto:akohlmey at cmm.chem.upenn.edu>   http://www.cmm.upenn.edu
> >       Center for Molecular Modeling   --   University of Pennsylvania
> >     Department of Chemistry, 231 S.34th Street, Philadelphia, PA
> >     19104-6323
> >     tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel:
> 1-215-898-5425
> >
> =======================================================================
> >     If you make something idiot-proof, the universe creates a better
> >     idiot.
> >
> >
> > ------------------------------------------------------------------------
> >
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> >
>
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